As disclosed in "Polydimethylsilane", JACS, 71, 963-4 (1964), C. A. Burkhard synthesized permethylpolysilane polymer (Me.sub.2 Si).sub.n. The synthesis proceeded from dimethyldichlorosilane and sodium metal as shown by the following formula: EQU Me.sub.2 SiCl.sub.2 +2Na.fwdarw.(Me.sub.2 Si).sub.n +2NaCl.
The polymer formed in this manner is an infusible solid for which there is no known technical use.
More recently, in Japan, Yajima et al have shown that a permethylpolysilane polymer of the right molecular weight range can be drawn into fibers. Also the fibers upon heating are transformed into fibers of .beta.-silicon carbide as shown by the following equation: ##EQU1## The resulting fibers are extremely strong. The tensile strengths claimed exceed those of any known material, including carbon and boron fibers now used to reinforce high temperature materials, such as turbine blades, wing edges of high performance aircraft, and the like.
Yajima et al obtain their permethylpolysilane polymer by thermolysis of dodecamethylcyclohexasilane, (Me.sub.2 Si).sub.6. When (Me.sub.2 Si).sub.6 is heated to 400.degree. C., it undergoes ring-opening polymerization to give polymers of various molecular weights. This product is solution fractionated since only polymers in the right molecular weight range can be spun or drawn into fibers.
It is a principal object of this invention, therefore, to provide a polymer that can be used directly to form fibers.
Another object of the invention is to provide a phenylmethylpolysilane polymer which undergoes thermolysis to silicon carbide.
Another object of the invention is to provide a process for preparing the phenylmethylpolysilane polymers.
Other objects and advantages of the invention will be apparent to those skilled in the art upon consideration of the accompanying disclosure.